The present invention relates to a method and device for improving the effects of at least one movable high pressure nozzle producing a high pressure jet of pressurized fluid, particularly in a high pressure washer. The jetting direction of the high pressure jet is continuously changed by action of the pressurized fluid.
According to German Patent 3 419 964 a device is known having a rotating pencil jet nozzle directly connected to a turbine wheel. In this device it is disadvantageous that the entire outer sliding diameter D of the rotating nozzle member must move over the complete circumference, resulting in high friction, heat generation and increased wear, which, in turn, causes reduced load capacity and shortens the life of the device. According to German Patent DE-GM 88 07 562.1 it is known to reduce these negative effects by a slim seal edge working against a sealing surface. However the principal disadvantages remain, since at constant nozzle rotation speed the same and possibly an increased rotational displacement must occur with possibly correspondingly increased friction. German Patent 34 19 964 describes a device having similar problems. According to German Patent 36 23 368 a nonrotating nozzle is moved within a ball joint, so that the jet describes a conical shape, producing a smaller effective friction diameter d and a reduced displacement during rotation, .pi. d. However despite some improvement, the desired lengthening of the life of the device does not take place. According to German Patent DE-Gbm GM 80 29 704 a nozzle is swiveled back and forth within a certain angle. The reduced angular displacement is advantageous. However the increased diameter D for jet rotation again results in the same disadvantages. According to German Patent DE-GM 8 029 704 and German Published Patent Application DE-OS 37 24 65, the nozzle can be supported by a ball joint. In this device it is still disadvantageous that no relatively constant sliding speed over a working rotation angle can be achieved (in particular the sliding speed is considerable, when the turbine cam is moving closest to the nozzle joint), so that the technically achievable load limits (namely the p.multidot.v-Factor as friction heat factor, i.e. the product of pressure p and sliding speed, v), cannot be fully utilized, since pressure p must be reduced, when speed v is increased to limit the friction so that the heat generation is acceptable.
In all these devices, it is disadvantageous that the technically possible load limits at a given nozzle frequency either determined by selection of a sliding diameter (thereby the sliding displacement is multiplied by .pi.) and/or by selection of a speed increase over a certain angular segment cannot be realized. In all these devices dirt carried along by the passing fluid will reach the sliding parts, thereby causing additional friction and wear. A full microfiltration of the complete fluid does not provide a feasible solution to the problem, since it is too expensive and difficult.
Finally the design of movable nozzles for situations requiring a long life with loads in excess of about 180 bar/2,500 psi has been impossible, since the three basic load problems at the sealing joint of these nozzles (sliding speed under pressure causing heat generation; constant sliding speed; and prevention of access of dirt) have up to now remained unsolved. In particular, the p.multidot.v-Factors formed an insurmountable barrier.